Citation

Segal NL, Roy A. Pers. Individ. Dif. 2001; 31(3): 445-452.

Copyright

(Copyright © 2001, Elsevier Publishing)

DOI

10.1016/S0191-8869(00)00149-5

PMID

unavailable

Abstract

Family resemblance for suicidal behavior has been interpreted by some researchers as reflecting extreme grief following loss. This view anticipates a higher frequency of attempted suicide among bereaved monozygotic (MZ) than dizygotic (DZ) twins (regardless of cause of death), given their generally increased social closeness. Alternatively, support for a genetic influence on suicidal behavior has been provided by findings of greater concordance among MZ than DZ twins, and among biological than adoptive relatives. The present study (a replication and extension of earlier work) attempted to reconcile these views. This was done by comparing the frequency of attempted suicide and suicidal ideation in 289 surviving MZ twins and 150 surviving DZ twins whose co-twins' deaths were non-suicides. Suicidal attempts (during the first two months following the loss) were recalled by four MZ twins (1.4%) and by five DZ twins (3.3%), a difference that was not statistically significant. This finding supports the view that suicidal loss of a close relative may trigger suicide in other family members only if they share relevant genetic predispositions. Suicidal ideation was reported by 80 MZ twins (28%) and by 35 DZ twins (24%), a non-significant difference. A significant, albeit modest, correlation between suicidal ideation and social closeness (r=0.16) suggests that twins sharing close social relations may experience and/or characterize their grief as suicidal ideation. Future analyses should classify participants with reference to specific subcategories of suicidal ideation, e.g., persistence of thoughts and intentions.